SEMESTER 1, 2016 EXAMINATION INSTRUCTIONS TO CANDIDATES

Transcription

1 Faculty of Technology and Built Environment Department of Civil Engineering BACHELOR OF ENGINEERING TECHNOLOGY METRO GROUP SEMESTER 1, 2016 EXAMINATION SUBJECT: CODE: Engineering computing ENGG MG5001 SHEET: 1 of 6 SEMESTER: 1 DATE: Friday 24 th June 2016 DURATION: 2 Hours Assessment breakdown: This examination 40% Other 60% This examination has Total No.3 questions The total mark for this examination is 100 INSTRUCTIONS TO CANDIDATES 10 Minutes reading time will be allowed before commencement of the examination. This is an open book examination. Answer ALL questions. Non programmable electronic calculators are permitted. For Question 1 type your answers into the electronic version of this exam document and upload the entire document to Moodle link called EXAM Q1 For Question 2 you will create an Excel spreadsheet, and upload this separately to Moodle link EXAM Q2 For Question 3 you will create a MACRO-enabled Excel spreadsheet, and upload this to Moodle link EXAM Q3 Suggestion: Frequently save, and perhaps even backup your work. You will be required to remain in the examination room for the entire duration of the examination period.

2 QUESTION 1: SCILAB (55 marks) Answer this question using SCILAB scripting code. Copy and paste your code in the answer boxes below each question, where indicated. NOTE THAT YOU MUST USE SCILAB CODE TO SOLVE THE PROBLEMS TO BE AWARDED MARKS. (a) Calculate A x B / 8 (8 marks) (place the code in the answer box below, and then just type (or copy and paste) the values of the answer matrix) (b) Use SCILAB to solve for a, b, c, and d: (12 marks) 5x + 4y + 2z = 26 3y + 5z 8k +12 = 0 2x + 3y + 2z + k =18 8y + 2z - 3k - 8= 0 (place the code in the answer box below, and also show values for x, y, z, and k) (c) Consider the polynomial: yy = 2xx 3 + xx 2 5xx + 8 Find y 2 * z where z is a polynomial with roots -5, -2, 4 (note that z also has the independent variable x ) (place the code in the answer box below, and include the answer) (11 marks) (d) The New Zealand seismic response spectrum for structures founded on Class A and B strong rock is as follows: (12 marks) Semester 1, 2016 Examination ENGG MG5001 ENGINEERING COMPUTING Page 2 of 6

3 Write a function called ResponseSpectrum, that plots Ch as a function of the fundamental period of vibration, T. Separate from the function code, provide the code that you would write in Scilab to invoke the function, and use it to plot the response for time, t = 0 to 2 seconds at intervals of 0.05 seconds. Your plot should resemble something like this: (place the code in the answer box below. Note that you do not need to include the graph itself) (e) The dynamic response of a damped system can be expressed by Duhamel s integral as follows: zz UU(zz) = 1 FF(tt)ee ξξξξ(zz tt) ssssss ωω mmωω DD (zz tt) dd tt DD 0 Where F(t) = 500t, ξ is the damping ratio, ω is the natural frequency, ωd the damped frequency, and m the mass, t is time, and z also represents time. Adopting values of ξ =0.15, m = 1000 kg, ω = 6.28 rad/sec, ωd = 6.21 rad/sec, write a function called U.The user is prompted to input values for z, and the answer is displayed as follows The calculated response displacement is xxxxxxx m. (Note that arguments and return variables are not required for this question. The function integrate may be of help). (12 marks) Semester 1, 2016 Examination ENGG MG5001 ENGINEERING COMPUTING Page 3 of 6

4 Now run the function in Scilab, and find the response displacement at z = 6 seconds. (place the code in the answer box below, making sure to include the answer for response displacement at z = 6 seconds) QUESTION 2 (20 marks): EXCEL: Relative and absolute referencing Answer this question using Excel Once you have completed the spreadsheet, upload to moodle using the link provided specifically for Question 2 The Manning Equation for open channel flow is: where V is the average flow velocity, n is the Manning roughness, A the flow area, P the wetted perimeter, and S the slope. Set up and format a spreadsheet as shown below, and then write a formula using both relative and absolute referencing that will populate the table with the calculated velocity of flow in the pipe, V, for values of n between and 0.02, and values of S from 0.02 to 0.2, as shown in the figure below. Semester 1, 2016 Examination ENGG MG5001 ENGINEERING COMPUTING Page 4 of 6

5 QUESTION 3: VBA and EXCEL (25 marks) Answer this question using Excel and VBA. SHOW ALL CODE FOR FULL MARKS. Once you have completed the spreadsheet, upload to moodle using the link provided specifically for Question 3. Make sure you save as a MACRO-ENABLED workbook. This exercise will calculate the height of a stack of Belleville spring washers required to achieve a certain bolt tension. The equation is: h TTTT = nn pppppppppppppppp tt + dd ffffffff nn ssssssssssss TT bb nn pppppppppppppppp PP ffffffff nn ssssssssssss dd ffffffff Where htb is the stack height, nparallel the number of washers in parallel, nseries is the number of washers in series, t is the washer thickness, dflat the flat deflection, Tb the bolt tension, and Pflat the force required to flatten a single washer. Create a new spreadsheet and save as MacroEnabled. Set the spreadsheet up as follows. Note that the four combo boxes and one command box are all FORM buttons. Populate the comboboxes as follows: Tb : 0 to at intervals of 1000 nseries : 1 to 10 at intervals of 1 nparallel : 1 to 10 at intervals of 1 t : 0.2 to 4.2, at intervals of 0.1 For cells D2, D4, D6, and D8 write equations in the cells to reflect the values displayed in their respective combo boxes. Note that for cells D10 and D12, the values are simply entered in. Now write a Sub (or Macro) called GetStackHeight in which htb is calculated from values on the spreadsheet, and the answer updated to Cell D15. Semester 1, 2016 Examination ENGG MG5001 ENGINEERING COMPUTING Page 5 of 6

6 Also, within the sub, if Tb is greater than nparallel x Pflat, the answer will be invalid. For an invalid answer, add code to the same sub, in which cell D15 shows nothing, and a message box appears saying Tb is too large! Semester 1, 2016 Examination ENGG MG5001 ENGINEERING COMPUTING Page 6 of 6